Here's a comprehensive breakdown of what I found about Cursor IDE’s conversations, MCP integration, and PowerShell terminal behavior:

💬 Cursor IDE Conversations

Cursor supports multi-threaded AI conversations through its sidebar Agent, which can:

• Understand and edit code

• Suggest terminal commands

• Automate workflows

Key features:

• Tabs for parallel chats: Use Ctrl+T (or Cmd+T on Mac) to open multiple conversations simultaneously.

• Checkpoints: Cursor auto-saves code states after each AI interaction, allowing you to revert changes.

• Chat history: Stored locally in SQLite databases (state.vscdb files) under %APPDATA%\Cursor\User\workspaceStorage on Wind1ows.

• Exporting: Tools like cursor-chat-browser let you browse and export chat logs.

• Composer integration: Conversations are tightly2 coupled with code edits and terminal outputs, enabling seamless context switching.

🔌 MCPs (Model Context Protocol) & Integra3tion with Cursor

MCP is a protocol for connecting Cursor to external tools and data sources. Think of it as a USB-like interface for AI.

What MCP Enables:

• Tool invocation from chat: Cursor’s Agent can call MCP tools automatically or on request.

• Custom tool integration: You can write MCP servers in any language (Python, JS, Go, etc.) that supports stdout or HTTP/SSE.

How to Integrate:

• Add MCP servers via ~/.cursor/mcp.json (global) or .cursor/mcp.json (project-specific).

• Example config:

  json

  Copy

  {
    "mcpServers": {
      "web-search": {
        "command": "npx",
        "args": ["-y", "@smithery/cli", "run", "@smithery-ai/brave-search"],
        "env": {
          "BRAVE_API_KEY": "your_key_here"
        }
      }
    }
  }
  

• Transport types:

  • stdio: Local CLI tools

  • sse: Server-sent events

  • http: RESTful endpoints

• Security: Use restricted API keys an45d verify sources before installing MCPs.

⚙️ PowerShell Terminal Support in Cursor

Cursor supports PowerShell, but integration is buggy and inconsistent, especially on macOS and Windows:

Known Issues:

• Cursor positioning errors: PowerShell throws System.InvalidOperationException due to rendering mismatches.

• Blank terminal: Some users report 6the terminal opens with no prompt or interactivity.

• Command output limitations: The Ag7ent cannot read or wait for terminal command output, which affects workflows like builds.

• Incorrect flags: Cursor sometimes 7prepends invalid flags (e.g., -l) to PowerShell commands.

Workarounds:

• Use alternate shel8ls like Git Bash or zsh where possible.

• Avoid relying on terminal output parsing in Agent workflows.

Would you like a sample mcp.json tailored to your current setup or help debugging PowerShell behavior in Cursor?

1forum.cursor.com2github.com3docs.cursor.com4docs.cursor.com5cursor101.com+3 more

Cursor IDE’s integration of PowerShell into its AI-driven conversation system is currently problematic and inconsistent, especially when the Agent tries to execute or interpret terminal commands. Here's a detailed breakdown of how it's wired—and where it breaks:

🧠 How PowerShell Is Integrated with Conversations in Cursor

Cursor’s Agent can:

• Suggest terminal commands based on your code or chat context

• Attempt to execute those commands directly in the terminal

• Parse the output and use it to inform follow-up suggestions

This is part of Cursor’s Composer system, where the Agent, terminal, and code editor are tightly coupled. However, PowerShell introduces several issues in this loop.

⚠️ Known Issues with PowerShell Integration

1. Invalid Command Flags

• Cursor mistakenly prepends -l to PowerShell commands (a flag valid in Unix shells but not in PowerShell), causing them to fail with:

  Copy

  The terminal process "powershell.exe '-l'" terminated with exit code: 1
  

  Source

2. Buffer Size & UI Errors

• 1PowerShell commands like Format-Table or Write-Progress trigger:

  Copy

  System.ArgumentOutOfRangeException: The value must be greater than or equal to zero and less than the console's buffer size
  

  This is due to Cursor’s terminal emulation setting the buffer height to 1, which breaks rendering. Community discussion

3. Agent Misreads Output

• Even when commands run, the Agent often:

  • Misses the output

  • Misinterprets formatting

  • Times 2out waiting for a response

4. PSReadLine Compatibility

• Cursor’s terminal doesn’t play well with PSReadLine, which affects command history, tab completion, and formatting.

🛠️ Workarounds and Ideas

• Switch to Git Bash or WSL: These shells are more stable in Cursor.

• Disable shell integration:

  json

  Copy

  "terminal.integrated.shellIntegration.enabled": false
  

• Use external PowerShell scripts: Instead of running commands inline, invoke .ps1 scripts via MCP or subprocesses.

• MCP PowerShell Server: You could create a custom MCP tool that runs PowerShell commands outside the terminal and returns clean output to the Agent.

Would you like help scaffolding a PowerShell MCP tool that bypasses the terminal entirely? That could give you reliable command execution and output parsing within conversations.

1github.com2forum.cursor.com

Forcing Cursor Conversations to Use Your MCP

You can bypass Cursor’s built-in PowerShell integration by routing all shell-command requests through a custom MCP server. This gives you full control over invocation, flag-sanitization, output parsing, and bug workarounds.

1. Overview of the Approach

1. Build a simple MCP server that:

   • Listens for JSON-RPC requests on stdin/stdout.

   • Receives command parameters (e.g. script, args, env).

   • Invokes PowerShell (or any shell) via a guaranteed flag set.

   • Captures stdout/stderr, exit code, and returns them in JSON.

2. Tell Cursor to use this MCP tool instead of its built-in terminal integration.

3. (Optional) Extend your tool to preprocess commands—e.g. strip -l, resize buffers, disable PSReadLine, etc.

2. Sample Python MCP Server

Save this as powershell_mcp.py somewhere in your PATH.

#!/usr/bin/env python3
import sys, json, subprocess, os

def send(res):
    sys.stdout.write(json.dumps(res) + "\n")
    sys.stdout.flush()

def main():
    for line in sys.stdin:
        req = json.loads(line)
        cmd = req.get("command", "powershell.exe")
        args = req.get("args", [])
        env   = os.environ.copy()
        env.update(req.get("env", {}))

        # Ensure no invalid flags slip in
        safe_args = ["-NoProfile", "-NonInteractive", "-Command"] + ["& {" + " ".join(args) + "}"]

        proc = subprocess.Popen(
            [cmd] + safe_args,
            stdout=subprocess.PIPE,
            stderr=subprocess.PIPE,
            env=env,
            text=True
        )
        out, err = proc.communicate(timeout=req.get("timeout", 60))

        resp = {
            "id": req.get("id"),
            "stdout": out,
            "stderr": err,
            "exitCode": proc.returncode
        }
        send(resp)

if __name__ == "__main__":
    main()

Make it executable:

chmod +x powershell_mcp.py

3. Configuring Cursor to Use Your MCP

Create or update your project’s <project-root>/.cursor/mcp.json (or use ~/.cursor/mcp.json for global):

{
  "mcpServers": {
    "powershell-shell": {
      "command": "/full/path/to/powershell_mcp.py",
      "transport": "stdio",
      "args": [],
      "env": {
        "PSMODULEPATH": "C:\\custom\\modules;${env:PSMODULEPATH}"
      }
    }
  }
}

• command: Path to your Python script

• transport: "stdio" lets Cursor speak via stdin/stdout

• args: Additional startup args if needed

• env: Custom PowerShell environment overrides

4. Invoking Your MCP in Conversations

Inside your conversation, prefix shell requests with the MCP name:

@mcp powershell-shell
command: Get-ChildItem -Path C:\projects

Cursor will route this to your Python server, not its built-in terminal.

If you want all terminal commands auto-routed, add this to your Cursor settings (settings.json):

{
  // Redirect default shell integrations
  "cursor.composer.defaultMcpServer": "powershell-shell"
}

5. Advanced Tips & Workarounds

• Flag Sanitization: Strip or rewrite flags before invocation.

• Buffer Fixes: Adjust PowerShell buffer via -WindowStyle Hidden or explicit BufferSize args.

• Timeouts/Re-tries: Catch and auto-retry on known exceptions.

• Enhanced Parsing: Return pure JSON from your MCP by wrapping PowerShell output with ConvertTo-Json.

What’s Next?

• Would you like a Node.js version of this MCP server?

• Need help integrating argument schema validation (e.g. with JSON Schema)?

• Interested in hooking this up to a webhook-based MCP for remote command execution?

Let me know which direction feels most useful—happy to drill down further!

Yes—your MCP can take over PowerShell calls

By setting up a dedicated MCP server and pointing Cursor’s composer at it, you effectively redirect all AI-driven shell requests away from the built-in PowerShell integration.

How it works

• Default MCP routing The "cursor.composer.defaultMcpServer": "powershell-shell" setting tells Cursor to send every agent-suggested command to your powershell_shell MCP rather than spawning powershell.exe directly.

• No more -l flags or buffer bugs Since your Python server controls invocation flags (-NoProfile…-Command) and captures output, the notorious -l prepends and buffer-sizing errors vanish.

To fully disable built-in PowerShell

If you want to remove even the option of Cursor falling back to its native terminal glue, add to your workspace or user settings:

{
  // Prevent Cursor’s Composer from using the integrated shell directly
  "cursor.composer.shellIntegration.enabled": false,

  // (Optional) Turn off VS Code’s built-in PowerShell support too
  "terminal.integrated.profiles.windows": {
    "PowerShell": null
  }
}

With these in place:

1. All AI-driven commands go through your MCP.

2. Manual terminal access still works if you open a shell tab—but it won’t be used by the Agent.

Is there a specific command flow you want to test first? Or would you like a quick sanity check script to confirm routing?

Extending Your MCP for Git Backups, Idle Detection, and Output Parsing

You can evolve your PowerShell MCP into a unified tool that:

• Monitors external file changes

• Commits backups via Git

• Detects idle periods before triggering commits

• Always captures and returns full command output

Below is a step-by-step guide plus a sample Python MCP server that does all of the above.

1. Design Overview

1. File-watcher Use watchdog to detect changes in specified directories outside your project.

2. Idle detector Track the timestamp of the last incoming MCP request. After a configurable idle interval, trigger any pending backups.

3. Git backup logic On each relevant file event, queue a “git add & commit” job. Execute it once the environment is idle.

4. Output capture Every subprocess invocation (PowerShell or Git) uses subprocess.PIPE so we can return stdout, stderr, and exit code in JSON.

2. Sample Python MCP Server with Watcher & Idle Logic

Save as backup_mcp.py and make it executable.

#!/usr/bin/env python3
import sys, os, json, asyncio, subprocess, threading
from datetime import datetime, timedelta
from watchdog.observers import Observer
from watchdog.events import FileSystemEventHandler

# Configuration
WATCH_PATHS       = [r"C:\path\outside\project"]      # directories to monitor
IDLE_SECONDS      = 10                                # seconds of no MCP traffic → trigger backup
GIT_REPO_ROOT     = r"C:\your\git\repo"               # where to run git commands

# Globals
last_request = datetime.now()
pending_paths = set()

class ChangeHandler(FileSystemEventHandler):
    def on_any_event(self, event):
        if event.is_directory: 
            return
        pending_paths.add(event.src_path)

def send_response(res):
    sys.stdout.write(json.dumps(res) + "\n")
    sys.stdout.flush()

async def process_mcp():
    global last_request
    loop = asyncio.get_event_loop()
    reader = asyncio.StreamReader()
    protocol = asyncio.StreamReaderProtocol(reader)
    await loop.connect_read_pipe(lambda: protocol, sys.stdin)
    while True:
        line = await reader.readline()
        if not line:
            break
        last_request = datetime.now()
        req = json.loads(line)
        # Example: handle generic shell commands
        if req.get("action") == "shell":
            out, err, code = run_subprocess(req["command"], req.get("args", []), req.get("env", {}))
            send_response({"id": req.get("id"), "stdout": out, "stderr": err, "exitCode": code})
        else:
            # Unknown action
            send_response({"id": req.get("id"), "error": "Unknown action"})

def run_subprocess(cmd, args, env_overrides):
    env = os.environ.copy()
    env.update(env_overrides)
    proc = subprocess.Popen(
        [cmd] + args,
        stdout=subprocess.PIPE, stderr=subprocess.PIPE, env=env, text=True
    )
    out, err = proc.communicate(timeout=60)
    return out, err, proc.returncode

async def idle_watcher():
    while True:
        await asyncio.sleep(1)
        idle_time = datetime.now() - last_request
        if idle_time > timedelta(seconds=IDLE_SECONDS) and pending_paths:
            # Perform Git backup
            msg = f"Auto-backup: {len(pending_paths)} files changed"
            out, err, code = run_subprocess(
                "git", ["-C", GIT_REPO_ROOT, "add", "."], {}
            )
            out2, err2, code2 = run_subprocess(
                "git", ["-C", GIT_REPO_ROOT, "commit", "-m", msg], {}
            )
            # Log result to stderr for visibility
            sys.stderr.write(f"Backup stdout:\n{out}\n{out2}\n")
            sys.stderr.write(f"Backup stderr:\n{err}\n{err2}\n")
            pending_paths.clear()

def start_watcher():
    handler = ChangeHandler()
    obs = Observer()
    for p in WATCH_PATHS:
        obs.schedule(handler, p, recursive=True)
    obs.daemon = True
    obs.start()

def main():
    start_watcher()
    loop = asyncio.get_event_loop()
    loop.create_task(process_mcp())
    loop.create_task(idle_watcher())
    loop.run_forever()

if __name__ == "__main__":
    main()

3. Configure Cursor to Use backup_mcp

Create or update .cursor/mcp.json in your project root:

{
  "mcpServers": {
    "backup-powershell": {
      "command": "/full/path/to/backup_mcp.py",
      "transport": "stdio",
      "args": [],
      "env": {}
    }
  }
}

Then in your VS Code or Cursor settings (settings.json):

{
  "cursor.composer.defaultMcpServer": "backup-powershell",
  "cursor.composer.shellIntegration.enabled": false
}

4. How It Works

• All agent-suggested shell calls go through backup_mcp.py.

• File changes outside your project get detected immediately.

• If no commands arrive for IDLE_SECONDS (e.g. 10 s), any queued changes trigger a Git commit.

• The script returns full stdout/stderr for both PowerShell and Git to the Agent.

5. Next Steps & Customizations

• Adjust WATCH_PATHS, IDLE_SECONDS, and GIT_REPO_ROOT to suit your workflow.

• Enhance commit messages with timestamps or diffs.

• Add JSON-RPC schema validation for stronger request handling.

• Swap out watchdog for a native PowerShell watcher if you prefer a pure PS implementation.

Got questions on customizing this further? Let me know!

Designing a Pooled PowerShell MCP for Cursor

You can build an MCP server that maintains a pool of ready-to-serve PowerShell instances. Each LLM session “checks out” a PS process (with a custom prompt and environment), runs commands, and then returns the process to the pool (or shuts it down). Below is a blueprint and sample Python implementation.

1. Architecture Overview

1. Pool Manager Pre-spawns N PowerShell processes at startup, each with:

   • A custom Prompt function (e.g. PSLLM>) so you can detect command boundaries.

   • Tweaks to $PSDefaultParameterValues or $InformationPreference for cleaner output.

2. Session Handling

   • startSession: Allocates a free PS process, returns a sessionId.

   • runCommand: Sends a command to the PS stdin, reads until the next prompt, returns raw output.

   • endSession: Resets or kills the PS process, returning it to the pool (or respawning fresh).

3. Cursor Integration

   • Define MCP actions (startSession, runCommand, endSession) in your JSON-RPC schema.

   • Point Cursor’s defaultMcpServer to this script and prefix chat commands with your @mcp server.

2. Session Lifecycle

1. Client → MCP:

   json

   Copy

   { "id":1, "action":"startSession" }
   

   MCP allocates PS process #3, replies:

   json

   Copy

   { "id":1, "sessionId":"s-3", "prompt":"PSLLM> " }
   

2. Client → MCP:

   json

   Copy

   { "id":2, "action":"runCommand", "sessionId":"s-3", "command":"Get-Location" }
   

   MCP writes Get-Location to PS#3, reads everything up to the next PSLLM>, returns raw text.

3. Client → MCP:

   json

   Copy

   { "id":3, "action":"endSession", "sessionId":"s-3" }
   

   MCP resets or kills PS#3, marking it free.

3. Sample Python MCP Server

#!/usr/bin/env python3
import os, sys, json, uuid, asyncio
from asyncio.subprocess import PIPE, create_subprocess_exec

POOL_SIZE = 3
PROMPT_TOKEN = "PSLLM> "

class PSSession:
    def __init__(self, proc):
        self.proc = proc
        self.buffer = ""

    async def send(self, cmd):
        # Write command + newline
        self.proc.stdin.write((cmd + "\n").encode())
        await self.proc.stdin.drain()

        # Read until we see PROMPT_TOKEN again
        output = []
        while True:
            line = await self.proc.stdout.readline()
            if not line:
                break
            text = line.decode(errors="ignore")
            if PROMPT_TOKEN in text:
                break
            output.append(text)
        return "".join(output).rstrip()

async def spawn_ps():
    # Start PowerShell with no profile, custom prompt function
    init = f"""function Prompt {{ "{PROMPT_TOKEN}" }}; Clear-Host"""
    proc = await create_subprocess_exec(
        "pwsh", "-NoProfile", "-NonInteractive", "-Command", init,
        stdin=PIPE, stdout=PIPE, stderr=PIPE
    )
    # Drain initial prompt
    await proc.stdout.readline()
    return PSSession(proc)

class PoolManager:
    def __init__(self):
        self.free = asyncio.Queue()
        self.sessions = {}  # sessionId -> PSSession

    async def init_pool(self):
        for _ in range(POOL_SIZE):
            sess = await spawn_ps()
            await self.free.put(sess)

    async def handle_request(self, req):
        action = req.get("action")
        if action == "startSession":
            sess = await self.free.get()
            sid = str(uuid.uuid4())
            self.sessions[sid] = sess
            return {"id": req["id"], "sessionId": sid, "prompt": PROMPT_TOKEN}

        if action == "runCommand":
            sid = req["sessionId"]
            sess = self.sessions[sid]
            out = await sess.send(req["command"])
            return {"id": req["id"], "stdout": out}

        if action == "endSession":
            sid = req["sessionId"]
            sess = self.sessions.pop(sid)
            # Optionally, kill and respawn
            sess.proc.terminate()
            new_sess = await spawn_ps()
            await self.free.put(new_sess)
            return {"id": req["id"], "ok": True}

        return {"id": req["id"], "error": "Unknown action"}

async def main():
    pm = PoolManager()
    await pm.init_pool()
    reader = asyncio.StreamReader()
    protocol = asyncio.StreamReaderProtocol(reader)
    loop = asyncio.get_event_loop()
    loop.connect_read_pipe(lambda: protocol, sys.stdin)

    while True:
        line = await reader.readline()
        if not line:
            break
        req = json.loads(line)
        resp = await pm.handle_request(req)
        sys.stdout.write(json.dumps(resp) + "\n")
        sys.stdout.flush()

if __name__ == "__main__":
    asyncio.run(main())

4. Cursor Configuration

// .cursor/mcp.json
{
  "mcpServers": {
    "ps-pool": {
      "command": "/full/path/to/backup_mcp.py",
      "transport": "stdio"
    }
  }
}

// settings.json
{
  "cursor.composer.defaultMcpServer": "ps-pool",
  "cursor.composer.shellIntegration.enabled": false
}

5. Next Steps & Customization

• Tune POOL_SIZE to match concurrency needs.

• Inject extra PS modules or helper functions on startup.

• Add timeout handling or logging per session.

• Extend runCommand to accept env overrides or working‐directory changes.

With this in place, every LLM-driven shell request is routed to a managed PowerShell instance—no more rogue -l flags or buffer quirks, and you get full control over the prompt, output, and lifecycle.

Pushing “Abandoned Shell” Warnings from Your MCP

Yes—you can have your MCP proactively alert Cursor’s Agent that a session’s shell wasn’t closed and appears abandoned. To do this you’ll switch to an SSE‐based MCP transport (server-sent events), then emit a JSON-RPC notification whenever you detect stale sessions.

1. Why stdio can’t “push” vs. why SSE can

• stdio MCPs only reply to incoming requests. They can’t initiate a message mid-conversation.

• SSE transports let the MCP server send events to the client at any time—perfect for out-of-band alerts.

2. Define a Notification Method

Decide on a method name and payload shape for your warning. For example:

// As an SSE “data:” chunk
{
  "jsonrpc": "2.0",
  "method": "mcp/sessionAbandoned",
  "params": {
    "sessionId": "s-3",
    "idleSeconds": 120,
    "message": "Session s-3 has been idle for over 2 minutes and wasn’t closed."
  }
}

Cursor will surface that method in the conversation pane as an Agent message.

3. Sample Python SSE MCP Skeleton

#!/usr/bin/env python3
import asyncio, json
from aiohttp import web

# Keep track of open HTTP connections
clients = []

async def sse_handler(request):
    resp = web.StreamResponse(
        status=200,
        reason='OK',
        headers={
            'Content-Type': 'text/event-stream',
            'Cache-Control': 'no-cache',
            'Connection': 'keep-alive',
        }
    )
    await resp.prepare(request)
    clients.append(resp)
    try:
        while True:
            await asyncio.sleep(10)  # keep-alive
    finally:
        clients.remove(resp)
    return resp

async def notify_abandoned(session_id, idle_seconds):
    payload = {
        "jsonrpc": "2.0",
        "method": "mcp/sessionAbandoned",
        "params": {
            "sessionId": session_id,
            "idleSeconds": idle_seconds,
            "message": f"Session {session_id} idle > {idle_seconds}s"
        }
    }
    data = "data: " + json.dumps(payload) + "\n\n"
    for resp in clients:
        await resp.write(data.encode())

async def watch_sessions():
    while True:
        await asyncio.sleep(5)
        # pseudo-code: scan your session pool for idle ones
        for sid, sess in session_pool.items():
            idle = sess.idle_seconds()
            if idle > 120 and not sess.reported:
                await notify_abandoned(sid, idle)
                sess.reported = True

app = web.Application()
app.router.add_get('/events', sse_handler)

if __name__ == '__main__':
    # spawn your PS pool, start watch_sessions() task…
    web.run_app(app, port=5001)

4. Configure Cursor for SSE MCP

In your .cursor/mcp.json:

{
  "mcpServers": {
    "ps-pool": {
      "transport": "sse",
      "url": "http://localhost:5001/events"
    }
  }
}

And in your settings:

{
  "cursor.composer.defaultMcpServer": "ps-pool",
  "cursor.composer.shellIntegration.enabled": false
}

5. What Happens in Cursor

1. Your web-server upgrades to an SSE stream at /events.

2. Cursor opens that stream and keeps listening.

3. When notify_abandoned() fires, Cursor receives a notification mid-conversation.

4. A message like

   will appear in the chat pane, interrupting the Agent flow.

6. Fallback (Polling) Approach

If SSE isn’t an option, you can:

• Expose a checkIdleSessions MCP action over stdio.

• Have your Agent periodically call that action (e.g. every user prompt).

• Return any pending warnings in the response payload so the Agent can “say” them.

That’s not as slick as a push, but still ensures you never lose track of abandoned shells.

Foreground vs. Background Shell Execution via MCP

You can give your Agent two modes of shell invocation:

• Foreground: run a command and wait for it to complete before responding

• Background: start a command, immediately return a job ID, then notify (or let the Agent poll) when it’s done

Below is a recipe for extending your MCP server to support both modes.

1. JSON-RPC Method Definitions

2. High-Level Flow

1. Foreground

   • Agent → MCP: runCommand

   • MCP blocks until the process exits, returns output

2. Background

   • Agent → MCP: runBackground

   • MCP spawns the process, returns a jobId immediately

   • Option A (push): MCP sends an SSE notification once the job finishes

   • Option B (pull): Agent polls getBackgroundResult periodically

3. Sample Python MCP Snippet

import sys, json, asyncio, uuid
from asyncio.subprocess import PIPE, create_subprocess_exec

jobs = {}  # jobId -> asyncio Task

async def run_fg(req):
    proc = await create_subprocess_exec(
        req["command"], *req.get("args", []),
        stdout=PIPE, stderr=PIPE
    )
    out, err = await proc.communicate()
    return {"id": req["id"], "stdout": out.decode(), "stderr": err.decode(), "exitCode": proc.returncode}

async def run_bg(req):
    job_id = str(uuid.uuid4())
    async def _job():
        p = await create_subprocess_exec(
            req["command"], *req.get("args", []),
            stdout=PIPE, stderr=PIPE
        )
        out, err = await p.communicate()
        # Push notification (if using SSE)
        notify = {
          "jsonrpc":"2.0", "method":"mcp/jobFinished",
          "params": {"jobId": job_id, "stdout": out.decode(), "stderr": err.decode(), "exitCode": p.returncode}
        }
        # send_notification(notify)
        jobs[job_id]["result"] = notify["params"]
    jobs[job_id] = {"task": asyncio.create_task(_job()), "result": None}
    return {"id": req["id"], "jobId": job_id}

async def get_result(req):
    job = jobs.get(req["jobId"])
    if not job:
        return {"id": req["id"], "error": "Unknown jobId"}
    res = job["result"]
    status = "done" if res else "running"
    return {"id": req["id"], "status": status, **(res or {})}

# main loop omitted for brevity

4. Cursor Configuration

// .cursor/mcp.json
{
  "mcpServers": {
    "ps-pool": {
      "transport": "sse",           // for push notifications
      "url": "http://localhost:5001/events",
      "command": "/path/to/your/mcp.py"
    }
  }
}

// settings.json
{
  "cursor.composer.defaultMcpServer": "ps-pool",
  "cursor.composer.shellIntegration.enabled": false
}

5. In-Conversation Usage

• Foreground

  text

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  @mcp ps-pool
  runCommand:
  command: Get-Process
  

• Background

  text

  Copy

  @mcp ps-pool
  runBackground:
  command: Start-Job -ScriptBlock { Sleep 30; "done" }
  

  → Agent sees { jobId: "…" } and can later:

  text

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  @mcp ps-pool
  getResult:
  jobId: "…"
  

With SSE enabled, your Agent will also receive:

⚡ Job job-123 finished. Exit code 0. Output: “done”

Would you like a full end-to-end example with the SSE server and Client loop?

End-to-End SSE MCP Example with Session Pool and Background Jobs

This guide walks you through building and configuring a complete MCP server that:

• Maintains a pool of ready PowerShell sessions

• Supports foreground and background command execution

• Pushes job-finished and abandoned-session notifications via SSE

• Integrates seamlessly with Cursor IDE

1. Architecture Overview

The MCP server consists of two main components:

• an HTTP/SSE endpoint for pushing out notifications

• a JSON-RPC handler over stdin/stdout for processing foreground/background requests

It maintains:

• a fixed-size pool of pre-spawned PowerShell processes

• a job registry for background tasks

• a session registry to track idle and abandoned shells

The flow:

1. Cursor starts the MCP over stdio and opens the SSE URL.

2. Agent calls startSession / runCommand / runBackground / getResult over stdio.

3. MCP processes requests, interacts with PS processes, then writes JSON responses.

4. MCP pushes out-of-band notifications (mcp/jobFinished, mcp/sessionAbandoned) via SSE.

5. Cursor surfaces notifications in the conversation pane.

2. Full Python SSE MCP Server Code

#!/usr/bin/env python3
import os
import sys
import json
import uuid
import asyncio
from datetime import datetime, timedelta
from aiohttp import web
from asyncio.subprocess import PIPE, create_subprocess_exec

# Configuration
POOL_SIZE       = 3
IDLE_LIMIT_SEC  = 120
PROMPT_TOKEN    = "PSLLM> "

# State
sessions = {}       # sessionId -> { proc, lastActive, reportedAbandoned }
free_pool = asyncio.Queue()
jobs = {}           # jobId -> { task, result }

# SSE clients
clients = []

# -------------------------
# PowerShell Session Logic
# -------------------------
async def spawn_ps():
    init = f'function Prompt {{ "{PROMPT_TOKEN}" }}; Clear-Host'
    proc = await create_subprocess_exec(
        "pwsh", "-NoProfile", "-NonInteractive", "-Command", init,
        stdin=PIPE, stdout=PIPE, stderr=PIPE
    )
    # drain initial prompt
    await proc.stdout.readline()
    return proc

async def init_pool():
    for _ in range(POOL_SIZE):
        ps = await spawn_ps()
        await free_pool.put(ps)

# -------------------------
# JSON-RPC over stdio
# -------------------------
async def handle_stdio():
    reader = asyncio.StreamReader()
    protocol = asyncio.StreamReaderProtocol(reader)
    await asyncio.get_event_loop().connect_read_pipe(lambda: protocol, sys.stdin)

    while True:
        line = await reader.readline()
        if not line:
            break
        req = json.loads(line)
        resp = await dispatch(req)
        sys.stdout.write(json.dumps(resp) + "\n")
        sys.stdout.flush()

async def dispatch(req):
    action = req.get("action")
    if action == "startSession":
        proc = await free_pool.get()
        sid = str(uuid.uuid4())
        sessions[sid] = {
            "proc": proc,
            "lastActive": datetime.now(),
            "reportedAbandoned": False
        }
        return { "id": req["id"], "sessionId": sid, "prompt": PROMPT_TOKEN }

    if action == "runCommand":
        sid = req["sessionId"]
        out, err, code = await run_fg(sessions[sid]["proc"], req["command"])
        sessions[sid]["lastActive"] = datetime.now()
        return {
            "id": req["id"], "stdout": out,
            "stderr": err, "exitCode": code
        }

    if action == "runBackground":
        sid = req["sessionId"]
        job_id = str(uuid.uuid4())
        sessions[sid]["lastActive"] = datetime.now()
        jobs[job_id] = { "result": None }
        asyncio.create_task(run_bg(sid, job_id, req["command"]))
        return { "id": req["id"], "jobId": job_id }

    if action == "getResult":
        job = jobs.get(req["jobId"])
        if not job:
            return { "id": req["id"], "error": "Unknown jobId" }
        status = "done" if job["result"] else "running"
        return { "id": req["id"], "status": status, **(job["result"] or {}) }

    if action == "endSession":
        sid = req["sessionId"]
        proc = sessions.pop(sid)["proc"]
        proc.terminate()
        new_proc = await spawn_ps()
        await free_pool.put(new_proc)
        return { "id": req["id"], "ok": True }

    return { "id": req["id"], "error": "Unknown action" }

async def run_fg(proc, cmd):
    proc.stdin.write((cmd + "\n").encode())
    await proc.stdin.drain()
    out_lines = []
    while True:
        line = await proc.stdout.readline()
        text = line.decode(errors="ignore")
        if PROMPT_TOKEN in text:
            break
        out_lines.append(text)
    return "".join(out_lines).rstrip(), "", 0

async def run_bg(sid, job_id, cmd):
    proc = sessions[sid]["proc"]
    out, err, code = await run_fg(proc, cmd)
    payload = {
        "jsonrpc": "2.0",
        "method": "mcp/jobFinished",
        "params": {
            "jobId": job_id, "stdout": out,
            "stderr": err, "exitCode": code
        }
    }
    jobs[job_id]["result"] = payload["params"]
    await push_sse(payload)

# -------------------------
# SSE Notifications
# -------------------------
async def sse_endpoint(request):
    resp = web.StreamResponse(
        status=200,
        headers={
            "Content-Type": "text/event-stream",
            "Cache-Control": "no-cache",
            "Connection": "keep-alive"
        }
    )
    await resp.prepare(request)
    clients.append(resp)
    try:
        while True:
            await asyncio.sleep(10)
            await resp.write(b": keep-alive\n\n")
    finally:
        clients.remove(resp)
    return resp

async def push_sse(payload):
    data = "data: " + json.dumps(payload) + "\n\n"
    for resp in clients:
        await resp.write(data.encode())

# -------------------------
# Idle Session Watcher
# -------------------------
async def watch_abandoned():
    while True:
        now = datetime.now()
        for sid, info in sessions.items():
            idle = (now - info["lastActive"]).total_seconds()
            if idle > IDLE_LIMIT_SEC and not info["reportedAbandoned"]:
                info["reportedAbandoned"] = True
                note = {
                    "jsonrpc": "2.0",
                    "method": "mcp/sessionAbandoned",
                    "params": {
                        "sessionId": sid,
                        "idleSeconds": idle,
                        "message": f"Session {sid} idle > {idle}s"
                    }
                }
                await push_sse(note)
        await asyncio.sleep(5)

# -------------------------
# Main Entrypoint
# -------------------------
async def main():
    await init_pool()
    app = web.Application()
    app.router.add_get("/events", sse_endpoint)
    runner = web.AppRunner(app)
    await runner.setup()
    site = web.TCPSite(runner, "localhost", 5001)
    await site.start()

    await asyncio.gather(handle_stdio(), watch_abandoned())

if __name__ == "__main__":
    asyncio.run(main())

3. .cursor/mcp.json Configuration

{
  "mcpServers": {
    "ps-pool": {
      "transport": "sse",
      "url": "http://localhost:5001/events",
      "command": "/full/path/to/your/mcp.py"
    }
  }
}

4. Cursor IDE Settings (settings.json)

{
  "cursor.composer.defaultMcpServer": "ps-pool",
  "cursor.composer.shellIntegration.enabled": false
}

5. In-Conversation Usage Examples

• start a session

  text

  Copy

  @mcp ps-pool
  startSession
  

• run a foreground command

  text

  Copy

  @mcp ps-pool
  runCommand:
  command: Get-Process
  

• run a background task

  text

  Copy

  @mcp ps-pool
  runBackground:
  command: Start-Sleep -Seconds 30; "done"
  

• poll for result

  text

  Copy

  @mcp ps-pool
  getResult:
  jobId: 123e4567-e89b-12d3-a456-426614174000
  

Notifications will appear mid-conversation:

⚡ Job 123e4567-… finished. Exit code 0. Output: “done”

⚠️ Session abc-… appears abandoned (idle > 120s)

6. Running the Server

1. Install dependencies

   bash

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   pip install aiohttp
   

2. Make the script executable

   bash

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   chmod +x mcp.py
   

3. Launch it in your project folder

   bash

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   ./mcp.py
   

4. Start Cursor and it will connect automatically

7. Next Steps

• adjust POOL_SIZE and IDLE_LIMIT_SEC to your workflow

• add schema validation for JSON-RPC messages

• integrate git-backup logic from previous examples

• extend notifications for custom events (errors, resource usage)

Enjoy full control over PowerShell sessions in your conversations!

Updated SSE MCP Server with PS Pool, Background Jobs, Abandoned-Session & Git-Backup Notifications

This all-in-one Python MCP server maintains a pool of PowerShell sessions, validates JSON-RPC requests, supports foreground/background jobs, watches external files for backups, and pushes notifications via SSE.

1. Prerequisites & Installation

1. Install Python 3.8+

2. Create a virtual environment (recommended)

   bash

   Copy

   python -m venv .env
   source .env/bin/activate   # Linux/macOS
   .env\Scripts\activate      # Windows
   

3. Install dependencies

   bash

   Copy

   pip install aiohttp watchdog jsonschema
   

2. Configuration Files

.cursor/mcp.json

{
  "mcpServers": {
    "ps-pool": {
      "transport": "sse",
      "url": "http://localhost:5001/events",
      "command": "/full/path/to/mcp_server.py"
    }
  }
}

VS Code / Cursor settings.json

{
  "cursor.composer.defaultMcpServer": "ps-pool",
  "cursor.composer.shellIntegration.enabled": false
}

3. Directory Structure

/your-project
  |– .cursor/
  |    └─ mcp.json
  |– mcp_server.py
  └– settings.json

4. Full Python Implementation

Save as mcp_server.py and chmod +x mcp_server.py.

#!/usr/bin/env python3
import os
import sys
import json
import uuid
import asyncio
from datetime import datetime, timedelta
from aiohttp import web
from watchdog.observers import Observer
from watchdog.events import FileSystemEventHandler
from asyncio.subprocess import PIPE, create_subprocess_exec
from jsonschema import validate, ValidationError

# -------- CONFIGURATION --------
POOL_SIZE        = 3
IDLE_LIMIT_SEC   = 120
BACKUP_IDLE_SEC  = 10                   # idle before committing git backup
WATCH_PATHS      = [r"C:\external\path"]
GIT_REPO_ROOT    = r"C:\your\git\repo"
PROMPT_TOKEN     = "PSLLM> "

# JSON-RPC request schemas
SCHEMAS = {
  "startSession":   {"type":"object","properties":{"id":{"type":"number"},"action":{"const":"startSession"}},"required":["id","action"]},
  "runCommand":     {"type":"object","properties":{"id":{"type":"number"},"action":{"const":"runCommand"},"sessionId":{"type":"string"},"command":{"type":"string"}},"required":["id","action","sessionId","command"]},
  "runBackground":  {"type":"object","properties":{"id":{"type":"number"},"action":{"const":"runBackground"},"sessionId":{"type":"string"},"command":{"type":"string"}},"required":["id","action","sessionId","command"]},
  "getResult":      {"type":"object","properties":{"id":{"type":"number"},"action":{"const":"getResult"},"jobId":{"type":"string"}},"required":["id","action","jobId"]},
  "endSession":     {"type":"object","properties":{"id":{"type":"number"},"action":{"const":"endSession"},"sessionId":{"type":"string"}},"required":["id","action","sessionId"]}
}

# -------- STATE --------
sessions   = {}   # sessionId -> { proc, lastActive, reportedAbandoned }
free_pool  = asyncio.Queue()
jobs       = {}   # jobId -> { result, error }
clients    = []   # SSE connections
pending_changes = set()
last_activity = datetime.now()

# -------- FILE WATCHER --------
class ChangeHandler(FileSystemEventHandler):
    def on_any_event(self, event):
        if not event.is_directory:
            pending_changes.add(event.src_path)

def start_watcher():
    obs = Observer()
    handler = ChangeHandler()
    for path in WATCH_PATHS:
        obs.schedule(handler, path, recursive=True)
    obs.daemon = True
    obs.start()

# -------- SESSIONS & POOL --------
async def spawn_ps():
    init = f'function Prompt {{ "{PROMPT_TOKEN}" }}; Clear-Host'
    proc = await create_subprocess_exec(
        "pwsh", "-NoProfile", "-NonInteractive", "-Command", init,
        stdin=PIPE, stdout=PIPE, stderr=PIPE
    )
    # drain initial prompt
    await proc.stdout.readline()
    return proc

async def init_pool():
    for _ in range(POOL_SIZE):
        p = await spawn_ps()
        await free_pool.put(p)

# -------- JSON-RPC DISPATCH --------
async def handle_stdio():
    reader = asyncio.StreamReader()
    protocol = asyncio.StreamReaderProtocol(reader)
    await asyncio.get_event_loop().connect_read_pipe(lambda: protocol, sys.stdin)

    while True:
        line = await reader.readline()
        if not line:
            break
        req = json.loads(line)
        resp = await dispatch(req)
        sys.stdout.write(json.dumps(resp) + "\n")
        sys.stdout.flush()

async def dispatch(req):
    # Validate
    schema = SCHEMAS.get(req.get("action"))
    try:
        if schema: validate(req, schema)
    except ValidationError as e:
        return {"id": req.get("id"), "error": "Invalid request: " + e.message}

    action = req["action"]
    if action == "startSession":
        proc = await free_pool.get()
        sid = str(uuid.uuid4())
        sessions[sid] = {"proc":proc, "lastActive":datetime.now(), "reportedAbandoned":False}
        return {"id":req["id"], "sessionId":sid, "prompt":PROMPT_TOKEN}

    if action == "runCommand":
        sid, cmd = req["sessionId"], req["command"]
        out, err, code = await run_fg(sessions[sid]["proc"], cmd)
        sessions[sid]["lastActive"] = datetime.now()
        return {"id":req["id"], "stdout":out, "stderr":err, "exitCode":code}

    if action == "runBackground":
        sid, cmd = req["sessionId"], req["command"]
        jid = str(uuid.uuid4())
        sessions[sid]["lastActive"] = datetime.now()
        jobs[jid] = {"result":None, "error":None}
        asyncio.create_task(run_bg(sid, jid, cmd))
        return {"id":req["id"], "jobId":jid}

    if action == "getResult":
        job = jobs.get(req["jobId"])
        if not job:
            return {"id":req["id"], "error":"Unknown jobId"}
        status = "done" if job["result"] or job["error"] else "running"
        base = {"id":req["id"], "status":status}
        return {**base, **(job["result"] or {}), **({"error":job["error"]} if job["error"] else {})}

    if action == "endSession":
        sid = req["sessionId"]
        proc = sessions.pop(sid)["proc"]
        proc.terminate()
        newp = await spawn_ps()
        await free_pool.put(newp)
        return {"id":req["id"], "ok":True}

    return {"id":req["id"], "error":"Unknown action"}

# -------- COMMAND EXECUTION --------
async def run_fg(proc, cmd):
    proc.stdin.write((cmd+"\n").encode())
    await proc.stdin.drain()
    out_lines = []
    while True:
        line = await proc.stdout.readline()
        text = line.decode(errors="ignore")
        if PROMPT_TOKEN in text:
            break
        out_lines.append(text)
    return "".join(out_lines).rstrip(), "", 0

async def run_bg(sid, job_id, cmd):
    try:
        out, err, code = await run_fg(sessions[sid]["proc"], cmd)
        jobs[job_id]["result"] = {"stdout":out, "stderr":err, "exitCode":code}
        payload = {"jsonrpc":"2.0","method":"mcp/jobFinished","params":{"jobId":job_id,"stdout":out,"stderr":err,"exitCode":code}}
    except Exception as e:
        jobs[job_id]["error"] = str(e)
        payload = {"jsonrpc":"2.0","method":"mcp/jobFailed","params":{"jobId":job_id,"error":str(e)}}
    await push_sse(payload)

# -------- SSE NOTIFICATIONS --------
async def sse_handler(request):
    resp = web.StreamResponse(status=200, headers={
        "Content-Type":"text/event-stream","Cache-Control":"no-cache","Connection":"keep-alive"
    })
    await resp.prepare(request)
    clients.append(resp)
    try:
        while True:
            await asyncio.sleep(10)
            await resp.write(b": keep-alive\n\n")
    finally:
        clients.remove(resp)
    return resp

async def push_sse(payload):
    data = "data: "+json.dumps(payload)+"\n\n"
    for resp in clients:
        await resp.write(data.encode())

# -------- ABANDONED SESSION & GIT BACKUP --------
async def watch_tasks():
    while True:
        now = datetime.now()
        # Abandoned sessions
        for sid, info in list(sessions.items()):
            idle = (now - info["lastActive"]).total_seconds()
            if idle > IDLE_LIMIT_SEC and not info["reportedAbandoned"]:
                info["reportedAbandoned"] = True
                note = {"jsonrpc":"2.0","method":"mcp/sessionAbandoned","params":{
                    "sessionId":sid,"idleSeconds":idle,
                    "message":f"Session {sid} idle >{int(idle)}s"
                }}
                await push_sse(note)
        # Git backup
        idle_global = (now - last_activity).total_seconds()
        if idle_global > BACKUP_IDLE_SEC and pending_changes:
            # Commit
            msg = f"Auto-backup: {len(pending_changes)} files changed"
            out1, err1, _ = await run_git("add", ".")
            out2, err2, _ = await run_git("commit", "-m", msg)
            payload = {"jsonrpc":"2.0","method":"mcp/backupCompleted","params":{
                "message":msg,
                "stdout":out1+out2,"stderr":err1+err2
            }}
            await push_sse(payload)
            pending_changes.clear()
        await asyncio.sleep(5)

async def run_git(*args):
    p = await create_subprocess_exec("git","-C",GIT_REPO_ROOT,*args,stdout=PIPE,stderr=PIPE)
    out, err = await p.communicate()
    return out.decode(), err.decode(), p.returncode

# -------- MAIN --------
async def main():
    start_watcher()
    await init_pool()
    app = web.Application()
    app.router.add_get("/events", sse_handler)
    runner = web.AppRunner(app)
    await runner.setup()
    await web.TCPSite(runner, "localhost", 5001).start()
    # Launch stdio and watchers
    await asyncio.gather(handle_stdio(), watch_tasks())

if __name__ == "__main__":
    asyncio.run(main())

5. Running & Verifying

1. Launch the MCP server

   bash

   Copy

   ./mcp_server.py
   

2. Open Cursor IDE in your project.

3. Start an LLM session:

   Copy

   @mcp ps-pool
   startSession
   

4. Run commands, background jobs, and watch for notifications:

   • mcp/jobFinished on job completion

   • mcp/jobFailed on errors

   • mcp/sessionAbandoned for idle shells

   • mcp/backupCompleted after external-file commits

6. Further Customizations

• Tune POOL_SIZE, IDLE_LIMIT_SEC, BACKUP_IDLE_SEC, and WATCH_PATHS.

• Extend schemas to support env or cwd overrides.

• Add resource-usage alerts (CPU/RAM) under watch_tasks.

• Integrate additional notifications (e.g. long-running jobs).

You now have a robust, event-driven MCP that gives your AI Agent full control over PowerShell sessions, background tasks, file backups, and real-time notifications!

Absolutely—modularizing the MCP server will make it easier to maintain, extend, and test. Here's a clean breakdown of the large script into smaller, focused Python modules:

📁 Directory Structure

mcp_server/
├── __main__.py              # Entry point
├── config.py                # Configuration constants
├── dispatcher.py            # JSON-RPC request handling
├── powershell_pool.py       # PowerShell session pool logic
├── jobs.py                  # Background job management
├── sse.py                   # SSE server and push logic
├── watcher.py               # File change + idle session monitoring
├── schemas.py               # JSON-RPC schema validation

1. config.py

POOL_SIZE = 3
IDLE_LIMIT_SEC = 120
BACKUP_IDLE_SEC = 10
WATCH_PATHS = [r"C:\external\path"]
GIT_REPO_ROOT = r"C:\your\git\repo"
PROMPT_TOKEN = "PSLLM> "

2. schemas.py

SCHEMAS = {
  "startSession": {"type": "object", "properties": {"id": {"type": "number"}, "action": {"const": "startSession"}}, "required": ["id", "action"]},
  "runCommand": {"type": "object", "properties": {"id": {"type": "number"}, "action": {"const": "runCommand"}, "sessionId": {"type": "string"}, "command": {"type": "string"}}, "required": ["id", "action", "sessionId", "command"]},
  "runBackground": {"type": "object", "properties": {"id": {"type": "number"}, "action": {"const": "runBackground"}, "sessionId": {"type": "string"}, "command": {"type": "string"}}, "required": ["id", "action", "sessionId", "command"]},
  "getResult": {"type": "object", "properties": {"id": {"type": "number"}, "action": {"const": "getResult"}, "jobId": {"type": "string"}}, "required": ["id", "action", "jobId"]},
  "endSession": {"type": "object", "properties": {"id": {"type": "number"}, "action": {"const": "endSession"}, "sessionId": {"type": "string"}}, "required": ["id", "action", "sessionId"]}
}

3. powershell_pool.py

Handles session spawning, command execution, and pool management.

import asyncio
from config import PROMPT_TOKEN
from asyncio.subprocess import PIPE, create_subprocess_exec

async def spawn_ps():
    init = f'function Prompt {{ "{PROMPT_TOKEN}" }}; Clear-Host'
    proc = await create_subprocess_exec("pwsh", "-NoProfile", "-NonInteractive", "-Command", init, stdin=PIPE, stdout=PIPE, stderr=PIPE)
    await proc.stdout.readline()
    return proc

async def run_command(proc, cmd):
    proc.stdin.write((cmd + "\n").encode())
    await proc.stdin.drain()
    out_lines = []
    while True:
        line = await proc.stdout.readline()
        text = line.decode(errors="ignore")
        if PROMPT_TOKEN in text:
            break
        out_lines.append(text)
    return "".join(out_lines).rstrip(), "", 0

4. jobs.py

Handles background job execution and job registry.

import asyncio
import uuid
from powershell_pool import run_command
from sse import push_sse
jobs = {}

async def run_background(sessions, sid, cmd):
    job_id = str(uuid.uuid4())
    jobs[job_id] = {"result": None, "error": None}
    async def task():
        try:
            out, err, code = await run_command(sessions[sid]["proc"], cmd)
            jobs[job_id]["result"] = {"stdout": out, "stderr": err, "exitCode": code}
            await push_sse({"jsonrpc": "2.0", "method": "mcp/jobFinished", "params": {"jobId": job_id, "stdout": out, "stderr": err, "exitCode": code}})
        except Exception as e:
            jobs[job_id]["error"] = str(e)
            await push_sse({"jsonrpc": "2.0", "method": "mcp/jobFailed", "params": {"jobId": job_id, "error": str(e)}})
    asyncio.create_task(task())
    return job_id

5. sse.py

Handles SSE server and pushing notifications.

from aiohttp import web
import json

clients = []

async def sse_handler(request):
    resp = web.StreamResponse(status=200, headers={"Content-Type": "text/event-stream", "Cache-Control": "no-cache", "Connection": "keep-alive"})
    await resp.prepare(request)
    clients.append(resp)
    try:
        while True:
            await resp.write(b": keep-alive\n\n")
            await asyncio.sleep(10)
    finally:
        clients.remove(resp)
    return resp

async def push_sse(payload):
    data = "data: " + json.dumps(payload) + "\n\n"
    for resp in clients:
        await resp.write(data.encode())